1. Technical Field
The present invention relates to a storage system, and more particularly to a storage system that includes multiple disk drives.
2. Description of the Related Art
Storage systems that include multiple disk drives are known in the art as secondary storage systems connected to one or more computers. In recent years, there has been a trend toward increasing the storage capacities of such storage systems by including a large number of disk drives. For example, one key type of storage system for storing large amounts of data uses so-called MAID (Massive Arrays of Idle Disks) technology. In a storage system that employs MAID technology, there may be approximately 1000 disk drives for each storage system, enabling the storage of extremely large amounts of data. At the same time, when MAID technology is used, power consumption can be reduced and the useful life of the disk drives extended by limiting the number of simultaneously operating disk drives included in the storage system (to ¼ of such drives, for example).
In this type of system, a technology in which a large number of disk drives are housed in the three-dimensional fashion in a chassis is known. In this technology, improvements have been made in both the packaging density of the drives and the ease of maintenance and servicing.
However, in the above prior art technology, the disk drives arranged in a number of vertical tiers are cooled by a common cooling fan disposed at the top of the chassis. As a result, there is a danger that the drives at the lower tiers that are located some distance from the cooling fan cannot be sufficiently cooled.